Grid machine and the like



2 Sheets-Sheet 1 Oct. 24, 1939. c, A. NARWID GRID MACHINE AND THE LIKE Filed June 6, 1938 Q k N 1 ihllllml l Fl MN w Oct. 24, 1939. c. A. NARWID 2,176,919

GRID MACHINE AND THE LIKE Filed June 6, 1938 2 Sheets-Sheet 2 Fig.- 5 i f T INVENTORD l3 a BY Cyprian A. Narw/d I M} 33 firomzvs.

Patented Oct. 24, 1939 UNITED STATES PATENT OFFiCE GRID MACHINE AND THE LIKE Application June 6, 1938, Serial No. 212,161

14 Claims.

The present invention relates to machines for making grids for radio tubes and comprises an improved machine of this character which is provided with means for preventing or controlling S the bows or bends usually present in such grids.

The invention includes also a novel method of preventing or controlling during manufacture, the

occurrence of such bows or bends in the grid.

Grids for use in radio tubes and the like are 1 9 usually manufactured by notching support wires carried by a relatively rotating mandrel, winding the grid wire into the notches and fastening the grid wire into the notches, as by swaging. The support wires after the notching, winding and 13 swaging operations of conventional practice tend to bend or depart from a perfectly straight position with the result that undesirable bows or bends are formed in the finished grids.

One object of the invention is to control the degree of the bow or bend of the support wires: so as to avoid the undesirable bends or bows of the prior practice and to obtain grids approaching the straight or unbent character desired in practice.

Other objects of the invention will hereinafter appear.

For a better understanding of the invention reference may be had to the accompanying drawings forming a part of this application wherein:

. Fig. 1 is a side elevational view partly in section of the essential mechanism of a grid machine embodying the invention;

Fig. 2 is an end View of parts thereof;

Fig. 3 is a diagrammatic side view of one part of the machine;

Fig. 3a is a fragmentary view illustrating another form of mandrel;

Fig. i is a view indicating the undesirable bend or bow of the grid of conventional practice; and

Fig. 5 illustrates the character of the grid which may be obtained according to the present invention.

Referring to the drawings, there is shown a grid machine embodying the conventional notch 45 ing wheel I rotatably mounted between bearing screws 2 and 3 mounted in a frame a, a conventional swaging wheel 5 suitably supported by a frame 5, a conventional spindle I mounted in bearing 8 and carrying a mandrel 9, supply reels 8 for suppiying the support wires 5 l to the mandrel grooves 9, a reel 2 for supplying the grid wire it and a clamping head I for drawing the support wires l 5 along the grooves 9 of the mandrel 9.

These mechanisms operate as in conventional practice to draw the support wires II from the reels in through the machine, beneath the notching wheel I, and over the swaging wheel 5. The notching wheel I forms the notches indicated in the support wires ll for the reception of the 5 turns of wire l3. After positioning of the wire H3 in a notch, the swaging wheel 5 fastens the grid wire firmly to the support wire by the usual swaging operation, and as indicated in dotted lines in Fig. l the swager 5 is movable toward and 10 away from the mandrel 9 (by a mechanism omitted for convenience in illustration) for the purpose of discontinuing at desired intervals the swaging operations; these intervals of non-swaging corresponding to the lengths into which the grid is severed for use in radio tubes and the like. The mandrel e and clamping head M on the one hand and the notching wheel I and swaging wheel 5 on the other are relatively rotatable. In the particular embodiment shown the mandrel 9 is carried by the rotating spindle l (with which rotate the reels iii) while the notching wheel I and swaging wheel 5 are relatively fixed, though the wheels and 5 are journaled for rotation or oscillation about their respective axes and are adjustable toward and away from the mandrel. As the mandrel 9 is rotated that part of the support wires which projects above the grooves 9' in the mandrel a are engaged by the notching wheel l to form the notches and similarly the swaging wheel 80 engages the support wires at the notches to swage the grid wire !3 into fixed position on the supports.

In the production of the grids according to the conventional practice the support wires H tend to bend towards the notched side with the resultant bow formed in the grid. as indicated, slightly exaggerated, in Fig. 4. This renders the grid difficult to mount 'and assemble and the degree of bow or bend of the grid support wires in con- 40 ventional practice cannot be predetermined with any certainty.

In the embodiment of the invention herein shown a pair of pressure or holding rollers l5, disposed in advance of the wheel I are journaled .15 in the forked ends of lever arms i1 and caused to engage and hold the support wires ll firmly against bottoms of the grooves 9'. The arms I! are pivotally mounted in suitable slots on a collar l8 secured to the mandrel 9 and carry at their other ends adjusting screws 26 which bear upon the mandrel for adjustment of the pressure exerted by the rollers I5. Clamping screws 2! are provided for locking the adjusting screws 20 in their adjusted position. The depth of grooves 9' in the mandrel 9 decreases at 22 to a point where the support wires H project above the mandrel so as to be engaged by the rollers l5, notching Wheel l and swaging wheel 5.

outwardly directed pressure upon the support wires ll beyond the swaging wheel is eiiected by spreading the wires slightly apart as by an increase in the dimensions of the end of the mandrel 9 or by corresponding reduction in the depth of the grooves 9'. In the particular embodiment of the invention illustrated in Figs. 1 to 3, the spreading means comprise a plate member 23 of generally diamond shaped contour and with a dimension in the plane of the grooves 9 just slightly greater than that of the mandrel. Plate 23 is secured, as by a screw 24, to the reduced end of the mandrel. During operation of the mechanism, the plate member 23 rotates with the mandrel and exerts an outward pressure upon the support wires ll tending to spread them slightly apart, the latter running through grooves 23 formed on the opposite edges of the plate. The displacement or spread of the support wires under the influence of the plate or spreader 23 is shown slightly exaggerated in Fig. 3, where the distance d between each pair of dotted lines cor responds to the resultant outward displacement or spread of each support wire. An idler steel roller 26 positioned immediately beyond the spreader plate 23 and conveniently supported from the frame 4 by means of an adjustable bracket 21 carried by the bearing screw 2 is provided for engaging the outer edges of the support wires. This roller 26 rides upon the support wires H as the latter pass thereunder and tends to return them to parallelism in opposite to the spread effected by the plate 23.

The spreading means illustrated diagrammatically in Fig. 30. comprise the end 9a of the mandrel in which the grooves for the support wires being at a greater distance apart tend to spread the wires as they leave the mandrel, the spread being exaggerated for convenience in illustration.

With the proper adjustment of the mechanism described, the bend or bow of the grid support wires l l shown in Fig. 4 is substantially obviated and the straight controlled product, with parallel support wires of Fig. 5 is consistently produced. I have obtained particularly good results by the use of a spreader plate 23 having a spread of from .002 to .010 inch greater than that of the mandrel, namely, with d from .001 to .005 inch. Preferably only a slight pressure should be applied through the rollers l5, sufliciently to hold the wires ll firmly in the grooves 9, and positive spread should be given the support wires by the spreader plate 23 as indicated. The roller 26 is preferably adjusted so as to return the wires to parallelism and is applied near to the place at which the spreader plate contacts the wires. The roller 29 may be radially adjusted to any position desired through the adjustable connection of the slotted bracket 21 with the frame 4, it being only necessary to release and tighten the nut 2' for this purpose. Thus the grids, controlled as to the straightness desired, may be obtained at will.

Thus the bend or bow of the support wires is prevented or controlled by the application of radial pressure on the support wires both in advance of and beyond the notching wheel I. Where the support Wires are carried on the mandrel 9, the pressure is applied radially inward while beyond the notching wheel the pressure is applied radially outward, and just beyond this latter application of pressure, further inwardly directed pressure is applied. The effect of these various pressure applications upon the support wires is such that substantially all bending or bowing of the support wires of the finishing grid is eliminated and a controlled, uniform product, with straight support wires, such as is shown in Fig. 5, is obtained.

Obviously various changes might be made in the embodiment illustrated without departing from the spirit of the invention as defined in the accompanying claims.

Certain features of the invention herein set forth are claimed generically in my copending application Serial No. 269,399, filed April 22. 1939.

I claim:

1. In a machine of the character set forth, relatively rotating mandrel and wire notching means, said mandrel having a longitudinal groove on the surface thereof along which supporting Wire is fed, means disposed at a point in advance of the notching means for holding the wire firmly in the groove, said mandrel having a part disposed at a point beyond the notching means Whose guiding groove portion is displaced from the axis of the mandrel a slightly greater distance than the part of the groove disposed at the point where the notching means is located and a relatively rotating idler wheel disposed at a point beyond said guiding groove portion and journaled on an axis substantially parallel to the axis of the mandrel with the periphery of the wheel projecting towards the axis of the mandrel to a point slightly beyond the last named mandrel grooved guiding portion.

2. In a grid machine of the type having relatively rotatable mandrel and Wire notching means and means for feeding support wire along the mandrel and feeding grid wire to the notches formed by the notching means, in combination, a roller engaging the support wire at a point in advance of the notching means and holding the same against the mandrel at said point, means carried by said mandrel at a point beyond the notching means and engaging the support Wire in a manner to cause a slight bend thereof in a. direction opposite to the direction of pressure exerted by the roller and a roller disposed beyond the notching means and engaging the support wire in a manner to cause a slight reverse bend in said support wire as the support wire is drawn along the mandrel.

3. In a grid machine of the type having relatively rotatable mandrel and notching means and means for feeding a support wire along the mandrel and feeding grid wire to the notches formed by the notching means, in combination, means for engaging the support wire at a point in advance of the notching means and holding said support wire firmly against said mandrel at said point, said mandrel having'means thereon disposed at a point on the opposite side of the notching means from said holding means and engaging the support wire in a manner to cause a slight bend thereof in a direction opposite to the pressure applied by the holding means and means disposed further beyond the notching means for engaging the support wire and setting up therein a slight reverse bend as the support wire is fed along the mandrel.

4. In a grid machine of the type having relatively rotatable mandrel and notching means and means for feeding support wires along the mandrel and feeding grid wire to notches formed by the notching means, in combination, means engaging said support wires at points in advance of the notching means and holding the same firmly against the mandrel at said points, said mandrel having spreading means disposed at a point beyond the notching means and engaging the support wires in a manner to cause a slight spreading of the same at that point, and means disposed at a point slightly beyond said spreading means and engaging said support wires in a manner to cause a slight reverse bend therein as the support wires are fed along the mandrel.

5. In a machine of the character set forth. a rotating mandrel having a longitudinal groove on the periphery thereof, means for feeding a support wire along said groove, means for forming notches in said support wire as the latter is fed along said mandrel, means for feeding grid wire to said support wire and fastening the same in said notches, an adjustable roller engaging said support wire at a point in advance of the notching means and holding said support wire firmly in said groove, said mandrel comprising at a point beyond the notching means a part for en gaging the support wire which is of slightly greater radial dimensions than the similar dimension of the mandrel at the notching point and a radially adjustable idler wheel disposed beyond said part and engaging said wire to cause a slight inward bend therein as the support wire is fed along the mandrel.

6. In a grid machine of the type having relatively rotatable mandrel and wire notching means and means for feeding support wire along the mandrel and feeding grid wire to the notches formed by the notching means, in combination, a roller engaging the support wire at a point in advance of the notching means and holding the same against the mandrel at said point, a spreader plate disposed on the opposite side of the notching means from said roller and engaging said support wire in a manner to apply a slight outward bend thereto and a roller disposed beyond the spreader plate and engaging said support wire in a manner to cause a slight reverse bend of the support wire as the latter is moved along the mandrel past the spreader and the last named roller.

'7. In a machine of the character set forth, relatively rotating mandrel and wire notching means, said mandrel having a longitudinal groove 'on the surface thereof along which supporting wire is fed, said mandrel having a part disposed at a point beyond the notching means whose guiding groove portion is displaced from the axis of the mandrel a slightly greater distance than the part of the groove disposed at the point where the notching means is located and a relatively rotating idler wheel disposed at a point beyond said guiding groove portion and journaled on an axis substantially parallel to the axis of the mandrel with the periphery of the wheel projecting towards the axis of the mandrel to a point slightly beyond the last named mandrel grooved guiding portion.

8. In a grid machine of the character set forth, comprising relatively rotatable mandrel and notching means, and means for feeding support wire along the mandrel and for feeding grid wire to the notches formed by the notching means, the provision of means positioned in advance of the notching means for pressing the support wires inwardly against the mandrel and means beyond the notching means for exerting an oppositely directed pressure upon the sup-port wires, said last mentioned means including a spreader plate secured to the mandrel and additional means for applying pressure to the support wires, said additional means comprising a roller positioned adjacent the spreader plate to contact said wires and to exert a pressure thereon opposite to that exerted by the spreader plate and subsequent thereto.

9. In a grid machine of the type having a rotatable mandrel, notching means and a supporting member therefor, means for feeding support wire along the mandrel and for feeding grid wire to the notches formed by the notching means, the combination comprising adjustable rollers engaging the support wires and applying unyielding pressure thereto at points in advance of the notching means, a spreader plate secured to the mandrel and applying oppositely directed pressure to the support wires at points beyond the notching means and a roller mounted on the supporting member for the notching means just beyond the point of engagement of said spreader plate with the support wires for exerting inwardly directed pressure upon the support wires.

10. In a grid machine of the type having relatively rotating mandrel and notching means, means for feeding a pair of support wires along the mandrel and for feeding grid wires to the notches formed in said support wires by said notching means, the combination comprising means in advance of the notching means for applying pressure to the support wires radially of the mandrel and means beyond the point at which grid wire is supplied to the support wires for spreading the support wires slightly apart.

11. A machine according to claim 10 wherein said last mentioned means forces said support wires substantially from .002 to .010 inch apart.

12. A machine according to claim 10 including means adjacent to and beyond said spreading means for applying a pressure to said support wires in a direction tending to return said wires to parallelism.

13. A machine of the character set forth in claim 8, comprising means for exerting pressure against the support wire at a second point beyond the notching means.

14. In a grid machine of the character set (forth gcomprising relatively rotatable mandrel and notching means and means for feeding support wire along the mandrel and for feeding grid wire to the notches formed by the notching means, the provision of means for exerting pressure against said support wire at a point beyond the notching means and in the opposite direction to the pressure applied by the notching means, and means for engaging said support wire and applying pressure thereto at another point still further beyond said notching means and in the same direction as that exerted by the notchin: means.

CYPRIAN A. NARWID. 

